Within the welding industry there has been a long standing need to protect the vision and respiration of welders. Budmiger (U.S. Pat. No. 4,071,912; issued Feb. 7, 1978) is an example of a welder's mask which was specially designed to protect a welder's vision.
Although many welding helmets protect the welder's eyes from the intense light generated by the welding arc, the vapors and heat captured and generated between the welder and the helmet is a significant disadvantage. Consequently, various helmets were created that incorporated the use of internal ventilation and filter systems. The following disclosures relate to such helmets: Richey (U.S. Pat. No. 3,238,535; issued Mar. 8, 1966); Greenlee (U.S. Pat. No. 3,629,868; issued Dec. 28, 1971); Hoyecki (U.S. Pat. No. 3,921,223; issued Nov. 25, 1975); Budmiger (U.S. Pat. No. 3,943,573; issued Mar. 16, 1976); and Guzowski (U.S. Pat. No. 4,309,774; issued Jan. 12, 1982).
More particularly, Richey ('535) discloses a welding helmet having solar cells mounted thereon. The solar cells produce electrical power when energized by the incident light from an arc welding process. The electrical power is conveyed to a motor which rotates fan blades. The fan blades draw air toward the center of a tube. The air then passes through a longitudinal apertured slot and is directed downwardly along the interior of the front surface above the hood. The inlet ports of the tube are provided with cylindrical filter elements.
Greenlee ('868) discloses a complex adapter assembly for a welding helmet, wherein an electric motor and fan are detachably secured to the forward portion of a protective helmet so as, when actuated, to draw air into the mask or helmet generally about the operator's head and expelling such air through a forwardly directed opening formed in the mask. A mercury-type switch assembly, which performs according to the attitude of the helmet, is used to actuate the device. The fourth embodiment discloses the use of batteries which are immediately adjacent to the fan.
Hoyecki ('223) discloses an air shield comprising a hollow tube perforated along its length and contoured to encircle the neck of a welder. An exterior air supply is provided and attached to the device by means of a tube and on-off valve.
Budmiger ('573) discloses a protective helmet having a mini-fan and a cold air channel for supplying cooling air to the electronic and electromagnetic devices of a shading means and to an eye shade.
Guzowski ('774) discloses a ventilating helmet having an electrically operated fan which is adapted to move air to the interior of the helmet. The electrically operated fan is operated by a solar cell which is directly exposed to a source of light energy.
The teachings and devices disclosed in the foregoing patents have inherent difficulties. For example, solar cells often do not produce sufficient electrical power to properly rotate a fan. Solar cells also become easily broken and become covered with thick welding smoke. Each of these devices draws air either from a separate air supply line or from exterior areas of the hood. The maneuverability of the welder is severely restricted if use of a separate air hose is required. In other words, the welder must contend with a trailing air tube each time he or she wants to move. Air hose lines are cumbersome, expensive, and inconvenient. As a welder performs various tasks, there are times when he needs ventilation and times he does not. However, it is inconvenient for a welder to be switching the ventilator on and off during a period of work. An air supply obtained through an air hose is controlled manually with an on-off valve.
During a welding process, smoke and heavily contaminated air generally surround the welder. If air is drawn from the exterior areas of the hood, as taught in the prior art, then such contaminated air is drawn or blown past the facial area of the welder.
Many of the devices disclosed in the prior art are also very complex, expensive, and difficult to manufacture. Other difficulties include, the fact that if the bulk of the weight of such a device is located near the lower-most areas of the hood, it is difficult to maintain the hood in a raised position. If a mercury-type switch assembly is used and the hood is located in a lowered position, the switch assembly would actuate the motor, whether or not an arc had been struck.
Various brochures, such as those titled "RACAL Introduces POWERFLOW Air You Can Wear almost Anywhere!" and "3M Occupational Health & Safety Products", disclose other types of protective head and respiratory gear which do not pertain to the welding industry.
The inventor believes the known prior art taken alone or in combination neither anticipate nor render obvious the present invention. These citations do not constitute an admission that such disclosures are relevant or material to the present claims. Rather, these citations relate only to the general field of the disclosure and are cited as constituting the closest art of which the inventor is aware.